1. Field of the Invention
This invention relates generally to an apparatus and a method for slitting and for rolling elongated sheets of material, and more particularly to an apparatus and a method for controlling the uniformity and the density of the rolled material.
2. Description of the Prior Art
It has been common practice in prior art to feed paper from a wide payoff roll through a slitting mechanism and then to rewind the slitted strips of paper onto a mandrel.
The mandrel onto which the slitted paper is to be wound is customarily supported on a pair of supporting rollers and retained upon the supporting rollers by a riding roller disposed longitudinally thereupon. It has been common practice to drive all three of these rollers at constant peripheral speed by connecting them to a common drive source by sprockets and roller chains. In some cases, rotational torque to the second supporting roller and to the riding roller has been applied with friction clutches driven from a common drive. It has also been common practice to use weights, placed upon the riding roller mechanism, to urge the riding roller into contact with the mandrel, the purpose being to adjust the density of the roll being made.
There have been two deficiencies in apparatus built according to prior art. One of these deficiencies is that means for separately and adjustably urging the riding roller toward or away from the mandrel has not been provided. Thus when winding paper stock which varies in thickness from one edge to another, the roll becomes larger in diameter at one end than at the other with the result that the material tends to telescope off of the end of the roll. The other deficiency in prior art is that insufficient provision has been made for controlling the density of the rolled material. That is, the driving of the three rollers by sprockets, roller chain, and friction clutches has not provided for applying a reliable, repeatable, measurable and predetermined rotational torque to the second supporting roller and to the riding roller.
The present invention overcomes the limitations of prior art by providing means for individually and manually controlling the resilient forcing of both ends of the riding roller toward or away from the mandrel, thereby adding to or partially counterbalancing the weight of the riding roller. The present invention also overcomes the torque transmitting inaccuracy and indeterminability of friction clutches, and instead provides separate, predetermined, measurable, and manually adjustable rotational torque to the second supporting roller and to the riding roller so that the paper may be selectively tensioned between the respective rollers and so that the density of the roll can more effectively be controlled.